Epilepsy Syndromes You Should Recognize

Epilepsy is common, occurring in approximately 1 percent of people, with peak onset in infancy and childhood. It can have severe consequences in the developing brain, resulting in “hard wiring” for continued seizures and permanent cognitive, psychosocial, and motor delays. The critical factor in determining treatment and prognosis is recognizing the specific epilepsy syndrome.

Partial seizures, the other type, start in focal area of the brain and can spread to other areas. Simple examples of partial seizures (with no consciousness alteration) are “auras,” such as detecting a bad odor or taste, or experiencing déjà vu, jamais vu, or a feeling of dread. An example of a complex partial seizure (focally generated, but with alteration of consciousness) would be a staring spell, followed by head and eye deviation, with associated automatisms or stereotypic, repetitive movements.

Other signs and symptoms also help identify epilepsy syndromes: age of onset; clinical seizure semiology; medical history; developmental/academic history; family history; physical examination (including a complete neurologic examination); and diagnostic tests, including EEG, MRI, and other exams.

Infantile spasms

This is a commonly missed generalized epilepsy syndrome because the spasms can easily be confused for normal baby movements.

This syndrome typically occurs between 4 and 10 months. It is characterized by clusters of flexor or extensor “spasms” that frequently occur when an infant awakens, during drowsiness, or upon sleep. Spasms can be subtle, perhaps characterized only by a slight head drop or eye rolling, in clusters.

Causes of infantile spasms include brain malformations, infection, chromosomal abnormalities, stroke, inborn metabolism errors, or tumors. Early recognition is critically important as infantile spasms can develop into intractable epilepsy. If they are recognized within four to six weeks of onset, the ability to eliminate the infantile spasms and hypsarrhythmia EEG pattern is improved. The prognosis also is improved.

The therapy mainstay is adrenocorticotropic hormone (ACTH), injected daily for six to eight weeks. Prospective studies indicate that three-quarters of patients experience remission with this therapy. However, for children with tuberous sclerosis and infantile spasms, many physicians will use vigabatrin (Sabril) as a first-line therapy.

Infants with infantile spasms generally have a poor prognosis, with high risks of continued epilepsy, cognitive impairments, and developmental delays. This is a testament to the catastrophic consequences of even brief, recurrent seizures in developing brains.

Other generalized epilepsy syndromes include childhood absence epilepsy, juvenile absence epilepsy, and juvenile myoclonic epilepsy (JME) – all idiopathic with a probable genetic predisposition. Many such syndromes are secondary to mutations in the T-type calcium channel or gamma-aminobutyric acid channel.

Childhood absence epilepsy

It typically presents between ages 4 and 9 years. It is associated with absence seizures – brief episodes of staring, with no postictal phase, occurring multiple times daily – with a 17 percent chance of comorbid generalized tonic-clonic seizures. Ethosuximide and valproate are the only antiepileptic drugs with proven efficacy.

Juvenile absence epilepsy

It presents similarly to childhood absence epilepsy, but after age 10 years. The risk of generalized tonic-clonic seizures, in addition to absence seizures, is 80 percent.

Juvenile myoclonic epilepsy

JME presents at puberty, usually with generalized tonic-clonic seizures and myoclonic seizures in the morning. Absence seizures are less prominent or nonexistent. JME is lifelong epilepsy. Appropriate treatments include valproate, lamotrigine, or levetiracetam.

Benign rolandic epilepsy

Also called benign epilepsy with central-temporal spikes, it is the most common childhood epilepsy syndrome. Benign rolandic epilepsy is idiopathic, with a probable genetic predisposition, and generally surfaces in otherwise healthy, cognitively normal children between the ages of 5 and 8 years.

Seizures generally occur soon after falling asleep or in the morning between 4 a.m. and 6 a.m. They usually begin focally with facial twitching and drooling, followed by rapid secondary generalization to a tonic-clonic seizure. Typically infrequent, the seizures are commonly associated with sleep deprivation. The physical examination is normal, but a sleep-deprived EEG demonstrates drowsy and sleep-activated central-temporal spikes, usually bilateral. This syndrome goes into remission at puberty and does not always require antiepileptic medication.

Localization-related epilepsy syndromes

These syndromes that result from remote symptomatic lesions in the brain are more problematic. If the first one to two antiepileptic medications do not control the epilepsy, it is unlikely that additional antiepileptic medication trials will work. Even with complete seizure control, patients can rarely taper off medication. For patients whose seizures continue, epilepsy surgery may be the best option.

Studies confirm that surgery has a 67 to 90 percent chance of obtaining complete seizure control without yielding new neurologic deficits. Clinical studies also demonstrate improved quality of life and developmental outcomes.

Patients undergoing epilepsy surgery have less than 5 percent risk of bleeding, infection, and stroke, and less than 1% chance of death. When comparing these risks with those of continued seizures – depression, anxiety, suicidal ideation, academic failure, poor employment record, and sudden unexpected death in epilepsy or SUDEP – surgery is favorable.

Dravet syndrome

Pediatricians should also not miss Dravet syndrome, or severe myoclonic epilepsy of infancy. This syndrome usually presents at 4-6 months as complex febrile seizures.

Initially, the child’s development and interictal EEGs are normal. However, between age 1 and 4 years, the child develops febrile and afebrile seizures of multiple types, including generalized tonic-clonic, complex partial, tonic/atonic and myoclonic seizures. Interictal EEGs become epileptogenic, with multifocal and generalized discharges. Development falters and a slow but steady cognitive, psychosocial, and motor decline begins; 70 percent have autistic spectrum disorder.

As they age, patients have pes planus (flat feet) and a stooped ataxic gait. They often have sleep disturbances and cardiac abnormalities. These children have higher risks of SUDEP, and 18 percent have immunologic disorders. This epilepsy syndrome is difficult to control, but seizure management is typically optimized with a combination of antiepileptic medications: valproate, topiramate, clobazam, and ketogenic diet. Some common antiepileptic medications will worsen Dravet syndrome seizures: phenytoin, carbamazepine, oxcarbazepine and lamotrigine.

Dr. Zupanc is director of the Pediatric Comprehensive Epilepsy Program at Children’s Hospital of Orange County in Orange, California, and is professor of neurology and pediatrics at the University of California, Irvine. Dr. Zupanc disclosed she is on the advisory board and speakers bureau for Lundbeck and is a consultant to Questcor.

This article was originally published on July 30, 2014 in Pediatric News. Republished onto the CHOC Docs Blog with permission from Pediatric News.